The present invention relates to a GaN semiconductor light-emitting element and a method for manufacturing the same.
GaN semiconductor light-emitting elements having a three-dimensional shape which is pyramidal or which extends like a strip have been known, for example, from Japanese Unexamined Patent Application Publication Nos. 11-312840, 2002-335016, and 2003-218395. The GaN semiconductor light-emitting element disclosed in each of these Japanese Unexamined Patent Application Publications includes a base layer composed of a GaN-based compound semiconductor disposed on a substrate; a mask layer disposed on a top face of the base layer, the mask layer having an opening or an open region (hereinafter referred to as the opening or the like) which exposes a portion of the top face of the base layer; an underlying layer composed of a GaN-based compound semiconductor, the underlying layer being disposed on the top face of the base layer exposed in the opening or the like and extending over the mask layer in the vicinity of the opening or the like, the underlying layer having a three-dimensional shape; a first GaN-based compound semiconductor layer of a first conductivity type, an active layer composed of a GaN-based compound semiconductor, and a second GaN-based compound semiconductor layer of a second conductivity type disposed in that order on the underlying layer; a first electrode electrically connected to the first GaN-based compound semiconductor layer; and a second electrode disposed on the second GaN-based compound semiconductor layer.
In the GaN semiconductor light-emitting element disclosed in any of the Japanese Unexamined Patent Application Publications, the top face of the base layer is specifically the C plane. At least one face constituting the underlying layer is the S plane, and the inclination angle of such a face of the underlying layer with respect to the mask layer is 61.9 degrees because the top face of the base layer is the C plane.
Since the inclination angle of the face (i.e., S plane) constituting the underlying layer is large at 61.9 degrees as described above, the inclination angle of the second GaN-based compound semiconductor layer formed thereabove is also large. As a result, it is very difficult to form a second electrode on the second GaN-based compound semiconductor layer using a photolithographic step, such as a lift-off method.